Dicyclopentadienyl iron compositions and methods for curing polyester resins

ABSTRACT

NOVEL COMPOSITIONS AND METHODS EMPLOYING SAME ARE DISCUSSED AS USEFUL IN THE PEROXIDE INDUCED CURE OF POLYESTER RESINS. THE COMPOSITION AND METHODS EMPLOY A NEW PROMOTER SYSTEM HAVING, AS A PRINICPAL COMPONENT, A MONOSUBSTITUTED DICYCLOPENTADIENYL IRON COMPOUND, WHEREIN THE SUBSTITUENT IS A CARBONYL CONTAINING SUBSTITUENT, E.G. ACETYL, AND, AS SECOND COMPONENTS, A MEMBER(S) SELECTED FROM AN EXEMPLIFIED GROUP INCLUDING VARIOUS PHOSPHOROUS COMPOUNDS, AN ASCORBIC ACID COMPOUND, A STANNOUS SALT OR SOAP, OR AN AMMONIUM OR ALKALI METAL HYDROGEN SULFITE.

United States Patent 3,830 876 DICYCLOPENTADIENYL IRON COMPOSITIONS AND METHODS FOR CURHQG POLYESTER RESINS John J. Kracklauer, Boulder, Colo., assignor to Syntex Corporation, Panama, Panama No Drawing. Original application Oct. 26, 1970, Ser. No. 84,243, new Patent No. 3,753,927, dated Aug. 21, 1973. Divided and this application May 11, 1973, Ser.

Int. Cl. (108i 21/02 US. Cl. 260863 Claims ABSTRACT OF THE DISCLOSURE Novel compositions and methods employing same are discussed as useful in the peroxide induced cure of polyester resins. The compositions and methods employ a new promoter system having, as a principal component, a monosubstituted dicyclopentadienyl iron compound, wherein the substituent is a carbonyl containing substituent, e.g. acetyl, and, as second components, 3. member(s) selected from an exemplified group including various phosphorous compounds, an ascorbic acid compound, a stannous salt or soap, or an ammonium or alkali metal hydrogen sulfite.

This is a division of application Ser. No. 84,243 filed Oct. 26, 1970, which issued as Pat. No. 3,753,927 on Aug. 21, 1973.

The present invention relates to the art of effecting cure of polyester resins and to novel methods and compositions useful therefor. More particularly, the present invention is directed to effecting and improving the peroxide induced cure of polyester resin compositions by methods employing and compositions containing a promotor system of a specific class, to provide high quality product which can be notably free of color.

The art of curing polyester resins is fairly well developed-see U.S. Pats. 3,003,991, 3,238,274, and 3,480,- 561, for example--and various tests and standards have been developed which establish criteria for determining the eflicacy of various cure catalyst systems and the quality of final product. The various problems associated with developing efficient catalyst systems which provide acceptable product are also well recognized. Thus, various classes of accelerators for this purpose have been proposed, such as metal salts, e.g., salts of iron, cobalt, and vanadium (including the naphthenates) either alone or in combination with an acid phosphate, ester or benzene phosphinic acid; Lewis acids; ferrocene; amines; and so forth. However, the art is still in need of a promotor or accelerator system which in use can combine the advantageous features of high quality cure and low color product with general high order eificacy.

The present invention provides for an accelerator or promotor system which, because of its unique combination of components, give superior cure effect with high quality lower color product. By virtue of the present invention the disadvantages inherent or otherwise associated with the prior art catalyst or promotor systems are overcome. Thus, in many instances, the novel system of the present invention is superior in eflect to the prior art systems, both in the rate and quality of cure and the quality of (low color) product.

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The present invention is directed to a novel composition useful in the cure of an unsaturated polyester resin which comprises:

(a) a mono substituted dicyclopentadienyl iron compound 5 of the formula:

0 this wherein R is hydrogen, lower alkyl, lower alkyloxy, or phenyl; and

(b) at least one member selected from the group consisting of a phosphorus compound characterized by the said (a) and (b) components optionally dispersed in a mutual solvent.

The novel composition of the present invention will contain a mono substituted dicyclopentadienyl compound as defined above and at least one member selected from the phosphorous compound, ascorbic acid compound, stannous salt or soap, and amomnium or alkali metal hydrogen sulfite, or carbonyl addition product thereof, all as defined above. In the preferred embodiments, one such member is present and is selected from the phosphorous compound or two or more such members are present, one of which is selected from the phosphorous compound, the phosphorous compound being as defined above, preferably phosphoric acid, phosphorous acid, and hypophosphorous acid.

The present invention is also directed to a novel method useful in the cure of an unsaturated polyester resin which comprises: incorporating in said resin a promoting amount of the composition as above defined.

This novel method of the present invention thus involves dispersing the novel composition as defined above in the polyester resin to be cured. Thus, in those instances wherein a mutual solvent is present and is selected from a polyester resin, the novel method hereof comprises the preparation of a novel composition hereof. The present invention is also directed to a novel method useful in the cure of an unsaturated polyester resin which comprises incorporating in said resin a promoting amount of the composition as above defined and a catalytic amount of a peroxide initiator.

The present invention is further directed to a novel composition comprising an unsaturated polyester resin, an ethylenically unsaturated monomer copolymerizable with said unsaturated polyester resin, and a promoting amount of the composition as above defined.

The present invention is further directed to a novel composition comprising an unsaturated polyester resin, an ethylenically unsaturated monomer copolymerizable with said unsaturated polyester resin, a promoting amount of the composition as above defined and a catalytic amount of a peroxide initiator.

The mutual solvent for the two components of the novel compositions hereof is optionally employed. The nature of the solvent, if employed, is not critical to the present invention. Included are the monoand di-alkyl ethers of diethylene and triethylene glycol, e.g., diglyme and triglyme; Cellosolves; and other common organic solvents such as dioxane, tetrahydrofuran, benzene, toluene, hexane, octane, and the like. In addition, the mutual solvent, if employed, includes the particular unsaturated polyester resin to be cured.

Representative mono substituted dicyclopentadienyl iron compounds of the present invention includes:

formyldicyclopentadienyl iron, acetyldicyclopentadienyl iron, propionyldicyclopentadienyl iron, butyroyldicyclopentadienyl iron, pentanoyldicyclopentadienyl iron, hexanoyldicyclopentadienyl iron, carbomethoxydicyclopentadienyl iron, heptanoyldicyclopentadienyl iron, octanoyldicyclopentadienyl iron, carbethoxydicyclopentadienyl iron, carbopropoxydicyclopentadienyl iron, carbobutoxydicyclopentadienyl iron, benzoyldicyclopentadienyl iron,

and so forth.

The phosphorus compound of the present invention is selected from those wherein the phosphorus atom is in the +3 valence state and/or is bonded to at least one hydrogen atom and/or hydroxyl group. Representative phosphorus compounds include the alkyl acid phosphites, alkyl acid phosphates, phosphoric acid, hypophosphorous acid, phosphorous acid, trialkyl phosphites, and triarylphosphites such as dimethyl phosphite, diethyl phosphite, dibutyl phosphite, dihexyl phosphite, dioctyl phosphite, methyl acid phosphate, ethyl acid phosphate, butyl acid phosphate, acid phosphate, octyl acid phosphate, trimethyl phosphite, tributyl phosphite, trioctyl phosphite, triphenyl phosphite, phosphorous acid residues, and the the like.

The useful ascorbic acid compounds hereof include the d, l, and raecmic isomers of ascorbic acid. Alkali metal hydrogen sulfites are for example, sodium hydrogen sulfite and potassium hydrogen sulfite. The useful stannous salts hereof include both inorganic and organic salts. Representative stannous salts and soaps include stannous sulfate, stannous napthenate, stannous octoate, stannous laurate, stannous hypophosphite, and the like.

The ratio of the amounts of the components of the composition hereof can vary over a wide range. Thus, whether or nor dispersed in a mutual solvent such as the polyester resin, the monosubstituted dicyclopentadienyl iron component and the phosphorus compound, if and when present, are present in a ratio of from about 50:1 to about 121000. Similarly, the monosubstituted dicyclopentadienyl iron compound to stannous salt ratio, if and when present, is from about 200:1 to about 1:500; mono substituted dicyclopentadienyl iron compound to ascorbic acid compound ratio, if and when present, from about 100:1 to about 1:100; and monosubstituted dicyclopentadienyl iron compound to ammonium or alkali metal hydrogen sulfite ratio, if and when present, from about 100:1 to about 1:100.

These relative amounts when translated into terms of concentration, when present in the polyester resin to be cured, range as follows:

P.p.m.

Monosubstituted dicyclopentadienyl iron compounds -1000 Phosphorus compounds -10,000 Stannous salt or soap 5-5000 Ascorbic acid compound 10-1000 Bisulfite compound 10-1000 The compositions hereof are prepared conveniently by simple mixing of the components.

In the present specification and claims, the term polyester refers to the poly condensation products of dicarboxylic acids or anhydrides with polyhydric alcohols. These unsaturated polyesters can also be modified in the polycondensation reaction mixture by the presence of monocarboxylic acid, monohydroxy alcohols, dihydroxy alcohols, and polycarboxylic acids. Useful, common polyester resins of the art include the esterificat-ion products of alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, 1,3-butylene glycol, glycerol, mannitol, and the bisphenol-A glycols, and unsaturated dicarboxylic acids such as maleic, fumaric, itaconic, and citraconic acids. These polyester unsaturated resins may be modified by replacement of the unsaturated dibasic acid with an equivalent quantity of another dicarboxylic acid such as, for example, succinic, adipic, sebacic, phthalic, azelaic, tetrahydrophthalic, endomethylenetetrahydrophthalic, or hexachloroendomethylenetetrahydrophthalic acids.

The unsaturated polyester polymers as described above are cured in the presence of an unsaturated monomer capable of copolymerizing with the unsaturated polyester. Examples of such monomeric substances wellknown in the polyester art include styrene, vinyltoluene, divinylbenzene, methyl acrylate, methyl methacrylate, acrolein, the diallyl ester of endomethylene tetrahydrophthalic anhydride, ethylene glycol dimethyl acrylate, ethylacrylate, acrylonitrile, vinylacetate, diallyl phthalate, the vinyl phenols, diallyl maleate, triallylcyanurate, and so forth.

The polymerization catalyst used in the cure of the unsaturated polyester resins with the unsaturated monomer include the peroxides and the hydroperoxides used in the art. Examples of such catalysts include benzoyl peroxide, chlorobenzoyl peroxide, lauroyl peroxide, caprylyl peroxide, l-hydroxycyclohexyl hydroperoxide, methyl ethyl ketone peroxide, cumene hydroperoxide, sec-butylbenzene hydroperoxide, l-methyltetralin hydroperoxide, and so forth. Particularly preferred are ben- Zoyl peroxide and chlorobenzoyl peroxide. Generally, the peroxide catalyst is incorporated in amounts ranging from about 0.05% to about 3% by weight of the total polyester resin composition to be cured.

The monosubstituted dicyclopentadienyl iron compounds useful in the present invention are known and can be prepared in accordance with known procedures. For example, see JACS, 74, 3458 (1952), JACS, 74, 632 (1952) and Kealy & Pauson in Nature, 168, 1039 (1951).

Similarly, the other components of the compositions of the present invention are known compounds and can be prepared in accordance with known methods, for example, see Organophosphorus Compounds by Kosolapoif, John Wiley and Sons, New York, 1950.

The term lower alkyl refers to aliphatic straight, or branched chain groups of 1 to 4 carbon atoms and l and 2 and 4 and 1 to 2 to 4 carbon atoms; methyl, ethyl, propyl, butyl, the various isomers thereof. Lower alkyloxy is lower alkyl-O wherein lower alkyl" is as above defined.

The following examples serve to further illustrate the present invention.

EXAMPLE 1 A standard polyester resin composition is prepared containing the relative proportions of 1 mole each of maleic anhydride and phthalic anhydride and 2.2 moles of propylene glycol and a stabilizing amount of phosphorous acid. This polymer is diluted with 30% styrene containing 0.01% hydroquinone. The resultant mixture is divided into 50 gram samples. To an individual sample is added p.p.m. of one promotor composition (as listed below,

Table I) followed by 2% by weight of a 50% paste of benzoyl peroxide in each sample, with the following 6 EXAMPLE 4 Standard polyester resin compositions are prepared as results: described in Example 1 without the phosphorous acid TABLE I Promotor Gel Exo- Time to Cure conc., time, therm, exotherm, time, Product Promoter p.p.m. min. 0. min. hrs. color None. 1,500 Dicyclopentadienyliron 100 7 52 50 24 Yellow. Ethyldicyclopentadienyliron 100 7 46 15 24 Do. N,lI-dimethylaminomethyldicyclopenta- 100 105 40 315 24 De.

dlenyl iron.

Acetyldicyclopentadienyliron 100 25 137.5 63 Colorless.

1 63 minutes.

EXAMPLE 2 Standard polyester resin compositions are prepared as r and individually cured with acetyldicyclopentadienyl iron Co-component Poly- Gel Cure Exoconc., ester time, time, therrn, Product Co-component (percent) resm" min. min. color .AcFo cone, p.p.m.:

250 None 1 50 75 135 Yellow. 250.. Na S03, tnphenylphosphite- 1 1 55 80 128 Colorless. 250 Tnmethylphosphl 1 1 12 55 120 Do. 250 Tri-n-butylphosphite 1 1 20 70 120 Do. 250., Dimethylphesphate- 1 2 55 90 134 Do. 250,- Di-n-ectylphsphite 1 2 60 105 129 Do. 250 Hypiephosphorous acid 1 2 27 63 138 Do. 200 0 .1 2 34 74 127 Do. 200.- l 3:} 2 2a 65 133 Do.

Iseascorbic acid. 0. 05 250.. Z 0 0% 1 so 134 De.

scor 1c acl {IM-n-ectgl phogphite 0 1 1 4 19 136 soascor ic aci .02 25 {P phogphm O 0 2 54 122.5 Do.

soascer ic aci 3 {Pimethy ho hita g. 05 l 2 23 44 122 soascor ic aci .03 "ipimeth l hos mta g. g l 2 141 seascorbic aci 25 "{Pimethfi phoslphitm l 2 14 139's $09,800!- 10 3.01 "{Dimethyl phosphite 0.01 l 2 22 (I) 56 250 Ascorbic acid 2 6 22 137 Reduced color. 100 itanngus chlloride 2 43 82 136 Do.

scer 1e aci 200 "{gypoplfiosphlerous acig" )1 2 23 65 133 Colorless ypep esp orens aci 200 "{Stannous chloride 0. l 2 23 65 133 1 24 hours. 2 250 p.p.m. 3 200 p.p.m. 4 100 p.p.m. 5 1,000 p.11.

m. *1 denotes Reichhold Chemicals Inc. standard polyester resin #31-007. 2 denotes Kepper's Co. Inc. standard polyester resin #1000-25 described in Example 1 and individually cured with several systems as follows:

TABLE II Promoter Gel Time to cone, time, cure, Product Promoter p.p.m. nn'n. min. color Acetyldicyclepentadienyl iron 80 100 Colorless. n-Butyroyldicyclopentadienyl iron. 100 70 150 Do. Formyldicyclepentadienyl iron 200 30 Do. 100 90 150 Do.

Benzoyldicyclepentadienyl iron EXAMPLE 3 Standard polyester resin compositions are prepared as described in Example 1 without the phosphorous acid 0 to 5 scale.

When following the above procedure using 10,000 p.p.m. of dialkylphosphite and dialkylphosphate, good color reduction is observed and recorded in each instance.

What is claimed is:

1. A composition which comprises:

(a) a mono substituted dicyclopentadienyl iron compound of the formula:

wherein R is hydrogen, lower alkyl, lower alkyloxy, or phenyl; and

(b) at least one member selected from the group consisting of (1) a phosphorous compound characterized by the phosphorous atom having at least one of a +3 valence state, a bond with hydrogen, and a bond with hydroxy and selected from the group consisting of alkyl acid phosphites, alkyl acid phosphates, phosphoric acid, hypophosphorus acid, phosphorous acid, trialkyl phosphites, and triaryl phosphites; (2) an ascorbic acid compound selected from the group consisting of ascorbic acid and isoascorbic acid (3) a stannous salt or soap selected from the group consisting of stannous sulfate, stannous naphthenate, stannous octoate, stannous laurate, and stannous hypophosphite; and (4) an ammonium or alkali metal hydrogen sulfite;

said (a) and (b) components optionally dispersed in a mutual solvent;

(c) an unsaturated polyester which is a polycondensation product of one or more dicarboxylic acids or anhydrides with one or more polyhydric alcohols, and

(d) an ethylenically unsaturated monomer copolym erizable with said unsaturated polyester.

2. The novel composition according to Claim 1 additionally containing a catalytic amount of a peroxide initiator.

3. The novel composition according to Claim 2 wherein the peroxide initiator is benzoyl peroxide.

References Cited UNITED STATES PATENTS 3,242,112 3/1966 Renner et al. 260-23] FOREIGN PATENTS 1,241,109 5/1967 Germany.

OTHER REFERENCES Ferrocene Derivatives IV, H. J. Lorkowski and A. Wende, Chem. Abstracts 64, 98210 (1966).

WILLIAM H. SHORT, Primary Examiner E. A. NIELSEN, Assistant Examiner US. Cl. X.R. 252431 R, 431 P 

